47 



carry almost as much as a furrow. I may say at once that the 3.9-1 inches over the 

 whole area for cotton, even when the ground is not much cracked, is quite insufficient, 

 and in a long furrow that quantity would not reach the end. Of course, to equalize 

 the supply to each plant the field is divided longitudinally into narrow belts and 

 these belts crossways into short beds. This division is made after the field has 

 been prepared and ridged up, the original ridges stretching from one end of the 

 field to the other. Between each belt is a small water channel, which is what I 

 refer to in 4 (b). In these channels a good deal of water must be wasted. As to 

 the permanent waterways we calculate a mean loss of 10 per cent for absorption 

 and evaporation. * * * 



THE CAIRO BARRAGE. 



In 1798 and 1790, during- the French occupation, Napoleon called 

 attention to the advisability of constructing dams across the Rosetta 

 and Damietta branches of the Nile. Perennial irrigation had probably 

 not occurred to him, but he saw the advantage of being able to turn 

 the whole discharge of the river down one branch or the other so that 

 the lands along either might receive the benefit of the entire flow. 

 The dam would probably not have been built had this been its only 

 function, but his suggestion may have led Mohammed Ali to intro- 

 duce perennial irrigation in Lower Egypt. 



In 1833 Mohammed Ali favored building a stone dam across the 

 Rosetta Branch so that it might be entirely closed. This would raise 

 the level of the water considerably at the site of the dam and afford a 

 better supply to the canals taking water from the Damietta Branch, 

 along which was the larger irrigated area. Before work was begun 

 he was persuaded to change his plans. It was suggested to him that 

 in place of building a dam across the Rosetta Branch one be erected 

 on each branch 6 miles below their point of divergence. The khedive 

 approved this plan and ordered that the stone be taken from the Pyra- 

 mids. All protests against this latter scheme were without avail until 

 Linant Pasha, a government engineer, showed that, as the Pyramids 

 were built from the bottom to the top, they would have to be dis- 

 mantled from top to bottom, and that the stone thus procured would 

 be more expensive than if taken from new quarries opened near Cairo. 

 Everything seemed now to promise speedy completion of the dam. 

 Workshops were erected and some material for construction had been 

 delivered on the ground, when Mohammed Ali again changed his 

 mind and stopped the work. Nothing more was heard of the barrage 

 project until 1842, when Mougel Bey, a French engineer, was called 

 to Egypt and his plans, as altered by the khedive so as to include the 

 fortifications, led to the construction of the barrage as it stands to-day. 

 The dam was finally completed in 1801 at a cost of 89,000,000, not 

 counting the services of the corvee. The additional cost of fortifica- 

 tions, canal head gates, and incidentals made th(! total outlay about 

 $19,000,000. 



After this vast expenditure the dam was of no value except as a 



